important point regarding Vitamin A, its deficiency, treatment, prevention and control.

1. ADDIS ABABA UNIVERSITY COLLEGE OF VETERINARY MEDICINE AND
AGRICULTURE
INDIVIDUAL PRESENTATION ON VITAMIN “A” DEFICIENCY IN POULTRY
BY:
Akinaw Wagari
Instructor: Tilaye D. (DVM, MSc, Assistant Prof.)
June, 6/2015
Bishoftu, Ethiopia

2. Outlines
INTRODUCTION
IMPORTANCE
TYPICAL CLINICAL FINDINGS
TYPICAL GROSS FINDINGS
TYPICAL LIGHT MICROSCOPIC FINDINGS
POST-MORTEM LESIONS
DIAGNOSIS
TREATMENT
PREVENTION

3. 1. INTRODUCTION
Biochemistry starts by giving answer for innocent mankind question like:
 What is life?
 What is death?
 What is growth?
 Life is the organization of elements found on the earth. Whereas death is the disorganization
those of elements which form life.

4. Cont….
• Elements
• Molecules Macro-molecules Proteins, NA, CHO and Lipids
Micro-molecules Vitamins, hormones and minerals Biomolecules
• Fat soluble (ADEK) and water soluble
• Vitamin A is a generic term that refers to fat-soluble compounds found as preformed vitamin A
(retinol) in animal products and as provitamin A carotenoids in fruit and vegetables.
• The three active forms of vitamin A in the body are retinol, retinal and retinoic acid.

5. Cont…
• Vitamin A is involved in regulating the growth and specialization (differentiation) of virtually
all cells.
• It has important roles in normal immune functions; and eye development and vision.
• Its deficiency is occasionally seen in chickens and turkeys (insufficient vitamin A during 1-7
weeks of age). As other nutritional deficiencies, classic signs of deficiency are very rare in
commercial poultry fed complete diets.
• Its deficiency is associated with an increased susceptibility to infections, as well as to thyroid
and skin disorders.

6. Cont…
• Deficiencies of vitamins may occur following inappropriate formulation, the use of impotent
commercial preparations or destruction of nutrients in feed by oxidation.
• Avitaminosis A in chicks will show poor growth and feathering and in advanced cases, ataxia
(inability to stand), xerophthalmia (“dry eye”) and chronic purulent conjunctivitis (accumulation
of yellow caseous material beneath the eyelids).
• Laying hens subjected to avitaminosis A will show a deterioration in internal egg quality and a
high prevalence of blood spots. Fertility and hatchability of breeders will be adversely affected.

7. Cont…
• Diagnosis of avitaminosis can be confirmed by microscopic examination of the trachea and oral
mucosa.
• The characteristic change comprises squamous metaplasia, in which normal columnar epithelial
cells regress to multiple layers of flattened cells.
• Both immature and adult flocks will show kidney degeneration and the accumulation of urate in
the ureters.
• In advanced cases urate deposit on the viscera (visceral gout) => postmortem examination.

8. 2. IMPORTANCE OF VITAMIN A IN POULTRY
• Epithelial differentiation: Vit A deficiency -> impaired epithelial differentiation -> reduction in
mucus-secreting cells -> squamous metaplasia of respiratory and genitourinary epithelium -
> hyperkeratosis.

9. Vision
• Decreased synthesis of some glycoproteins and immunoglobulins by intestinal mucosa
> impaired local immunity.
• Vitamin A deficiency causes rapid depletion of retinal and rhodopsin, since it must be replaced
daily; results in “night blindness”.
• Corneal opacity

10. Growth
• Vit A deficiency -> retarded osteoclastic resorption of endosteal bone -> defective remodeling of
membranous bone -> asynchrony between developing CNS and bones of skull and spinal
column.
• Retarded growth

11. CNS
• Ostodystrophy/defective remodeling of skull bones -> increased intracranial pressure ->
cerebellum herniation into foramen magnum; cranial and spinal nerve degeneration;
hydrocephalus.
 Reproduction
• Vit A deficiency -> arrest of spermatogenesis at the spermatid phase in all species, especially in
cattle, rats and chickens.

12. Typical clinical findings
• Signs and lesions usually develop in 2-5 months depending on amount stored in the liver and
other tissues
• Chicks and poultry’s: Cessation of growth, hunched-up posture, emaciation, lethargy, mild
ataxia, swollen eyelids with a mucoid oculo-nasal discharge.

13. Cont…
• Laying hens: Decreased egg production with increased incidence of blood spots, emaciation,
weakness, ruffled feathers.
• Azotemia: Chronic Vit A deficiency also damages renal tubules.

14. Typical gross findings
• Small white nodules (1-3 mm) often with a central depression in nasal passages, mouth,
esophagus, pharynx and often into the crop.

15. Cont…
• Seromucoid watery masses fill turbinates and may cause facial swelling.
• The paranasal sinuses, trachea and bronchi may be lined by a delicate
pseudomembrane.
• Other lesions: bone deformities,
keratinization of the tongue,
corneal opacity

16. Typical light microscopic findings
• Dilation of submucosal glands; replacement of glandular epithelium with squamous metaplasia
• Atrophy and de-ciliation of respiratory cells +/- necrosis
• Bone lesions: Decreased endosteal and periosteal osteoblasts -> impaired bone growth, bone
remodeling and thin cortex.

17. Post-mortem lesions
• Eyelids inflamed and adhered
• Pustules in mouth and pharynx
• Excessive urates in kidneys and ureters

18. Diagnosis
• Signs, lesions, feed formulation
• Differential diagnosis
• Oral lesions
• Fowl pox(avian poxvirus): Raised nodules with necrotic centers in oropharynx and
esophagus
• Trichomoniasis (Trichomonas gallinae): Caseous proliferative lesions in buccal cavity,
pharynx, esophagus, crop, especially in pigeons and raptors
• Thrush (Candida albicans): Crop mucosa is thickened with white circular, raised plaques

19. Cont…
• Mucoid oro-nasal discharge and facial swelling
• Infectious coryza (Hemophilus paragallinarum): Profuse nasal discharge (“wet beak”)
• Infectious bronchitis (coronavirus): Swollen sinuses, catarrhal nasal and ocular discharge,
caseous exudate in lower trachea and bronchi

20. Cont…
• Neurologic signs
• Ataxia in severe deficiency may resemble Vitamin E deficiency; differentiation is by
histologic examination of the brain (Vitamin E deficiency causes encephalomalacia).

21. Vitamin A deficiency prevention
• Free-range chickens get their vitamin A from leafy greens, but chickens in an enclosure require
it in their feed.
• Supplementation of diet with vitamin A, antioxidant, good quality raw materials.

22. Vitamin A deficiency treatment
• Treatment consists of changing the chicken’s feed and of supplementing feed with vitamin A at
two to four times the normal level for two week (vitamin A in drinking water).
• A water-soluble vitamin A supplement is available for ease of administration.

23. Funny pictures

24. AMAZING!